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Does anyone have an idea how to configure SMTP attachment size to maximum size. I tried to send an email with an attached file of 2.5MB. It is working but if I tried with >2.5MB attachment file, then the mail does not send.

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Please tell us which SMTP server you are using. Exim, Postfix, Qmail, Sendmail, Exchange, Notes, etc.? – desasteralex Mar 14 '11 at 7:06
@desasteralex, the tags seem to suggest that he is using microsoft-smtp. – Zoredache Mar 14 '11 at 7:10
up vote 0 down vote accepted

Keep in mind that even if you increase the attachment limit on your server, your mail will still probably be rejected if you send it to other domains, as most sites keep the attachment size rather low.

The reason mail admins don't like to accept large attachments is that SMTP is a store-and-forward system, so any large attachments have to be copied (sometimes multiple times) on every server that touches the mail.

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